Scott Walker, Rick Perry, Rudy Giuliani: Polls go up, polls go down, game over.

Note the similar trajectories:

Source:  Real Clear Politics (2015) (2011-12)

Scott Walker as quoted in Reagan was behind in the polls, too.  (Politico, 9/18/2015)

As for Rudy.....Real Clear Politics doesn't start tracking until February 15, 2007.  We don't see his poll numbers going up, but we certainly see the slow slide through the summer and fall, followed by his falling off a cliff in February 2008.

And it's true that Reagan was behind in the polls in a 3-way race for the Presidency in 1980.  By the beginning of summer, however, he took and mostly maintained the lead.

He was nothing like 8 points behind 6 days before the election.

Source:  Wikipedia